Synthesis Of New Multifunctional Fluorescent Probe Based On AIE And Application In Gas Monitoring And Cell Imaging

Aggregation-induced emission（AIE）probe solves the defects of traditional organic fluorescent probe aggregation concentration quenching（ACQ）.It has been widely used in many fields because of its excellent photostability and easy modification.However,it is still an important research topic to design a simple,sensitive,multifunctional AIE probe with long fluorescence emission wavelength and good biocompatibility.Based on this,a series of efficient and simple AIE probes were designed and constructed in this paper,broke through the shortcomings of traditional probes such as complex synthesis steps and rely on organic systems.By rationally designing the molecular structure of AIE,the probe has good biocompatibility,low cytotoxicity and excellent optical properties.It is used to detect important ions and harmful gases in life systems and the environment.The specific research are as follows:1.A novel and simple probe with AIE property based on malononitrile and4-diethylaminobenzaldehyde was designed and synthesized.The detection mechanism was verified by high-resolution mass spectrometry（HRMS）,nuclear magnetic resonance spectroscopy（NMR）and dynamic light scattering（DLS）.Under the optimized experimental conditions,the detection limits（3σ/k,n=11）of this probe for Fe³⁺,CN^-and N₂H₄ were 0.17,0.39 and 0.15μM,respectively.This method has been successfully applied to the determination of the total amount of Fe³⁺and inorganic iron in actual samples,using Fe³⁺and EDTA to construct an ultra-sensitive suppression logic gate.The probe has low cytotoxicity,good biocompatibility,and excellent AIE characteristics.It has been successfully applied to CN^-imaging of living cells.At the same time,a portable solid state test paper was prepared,which successfully detected gaseous hydrazine molecules.This method realized the multifunctionalization of a simple fluorescent probe.2.A simple and efficient new AIE probe based on diaminomaleonitrile was designed for independent detection of residual hypochlorite and formaldehyde in the environment.For other potential competitors,the probe has high selectivity and excellent anti-interference ability for target detection.The detection of Cl O^-by the probe was fast,sensitive and visible to the naked eye.Cl O^-promoted the oxidative cracking of the C=N group of the probe solution,resulting in a significant change in the color of the probe solution and accompanied by fluorescence quenching.It has good linearity at 0.70–20μM,and the detection limit（3σ/k,n=11）was 18 n M.Formaldehyde aqueous solution between 0.50 and 25μM can be effectively detected by the probe with a detection limit（3σ/k,n=11）as low as 42 n M.A portable solid sensor–a formaldehyde detection plate was built by directly covering the probe on a thin-layer chromatography plate.Thereby,formaldehyde gas can be effectively and sensitively detected,which offers a clue for the developing solid-state formaldehyde detection plates.The high experimental recovery prove that the new probe was highly promising in hypochlorite detection in the real water environment.3.A fluorescence-enhanced probe based AIE was synthesized used a di（2-picolyl）amine（DPA）group as a highly selective metal chelating agent for Zn²⁺.The probe realized the combination with Zn²⁺in an environment where the volume fraction of water was 90%,and has good biocompatibility.The combination of the probe and Zn²⁺has a large Stoke shift（100nm）,and the obvious fluorescent color change of the probe can be seen with the naked eye,which makes it has high signal-to-noise ratio and high contrast,and minimizes self-absorption.Due to the high selectivity of the DPA group to Zn²⁺,the sensitivity of the probe to detect Zn²⁺was improved.Nuclear magnetic resonance spectroscopy（NMR）,high-resolution mass spectrometry（HRMS）,dynamic light scattering（DLS）and other methods have confirmed the mechanism of the probe for detecting Zn²⁺.Under the optimal experimental conditions,the linear fluorescence reaction of Zn²⁺occurred between 0.20 and 18μM.The detection limit（3σ/k,n=11）was 0.13μM.The low toxicity and excellent membrane permeability of the probe in living cells enable it to be efficiently applied for Zn²⁺imaging in cells.